Controls rods are used in nuclear reactors to control the rate of fission. In pressurized water reactors (PWRs), the control rods typically are arranged in control rod clusters. As shown in FIG. 1, each control rod cluster 10 can include a spider 12 with the control rods 14 vertically extending downwardly from the spider 12. The control rods 14 have a cladding 16, typically made of stainless steel or Ni-based alloy, fastened to the spider 12. The cladding 16 can have a bottom end cap 20 and a top end cap 22 to define a cavity 18. The cavity 18 is filled with one or more absorber bars 30, which are typically cylindrical and held by mean of a spring 24. The absorber bars for the control rod for a PWR often are made of silver, indium and cadmium, AgInCd. Absorber pellets, made for instance of B4C, may be interposed between the absorber bar 30 and the spring 24. The control rod cluster 10 can be lowered via the spider 12 into guide thimbles of the fuel assembly of a PWR to regulate the reactivity of the nuclear reactor core. During nuclear power reactor operation, the neutrons penetrate the control rod cluster 10 and the absorber bar material is activated and transmuted to other elements. The activation level depends on the accumulated irradiation of the material and the bottom section of the absorber bar 30 nearest the bottom end cap 20 introduced more deeply in the reactor core than the top section, has the highest neutron-activated radioactivity.
U.S. Pat. Nos. 4,928,291, 5,183,626 and 5,889,832 describe control rod clusters and are hereby incorporated by reference herein.
U.S. Pat. No. 4,650,606 describes cutting off used poison rods secured to a holder by a cutter and then storing them in a storage container.
U.S. Pat. No. 4,383,394 describes a cutting device for irradiated components such as nuclear fuel assembly parts.
Korean Patent Application Abstract 2006-0027472 describes an apparatus for automatically cutting a nuclear fuel control rod using a plurality of cutters that can reduce the time required for cutting the nuclear fuel control rod.
Japanese Patent Application No. 06-182414 describes a nuclear reactor spent guide tube cutting device.